1. Field of the Invention
The present invention relates to extending the useful life of a cutting edge. More particularly, the present invention relates to magnetically maintaining or restoring the sharpness of the cutting edge of any given blade.
2. Description of the Prior Art
Cutting edges on knives, scissors, and the like and on razor blades in particular have a limited useful cutting or shaving life. While abrasion and friction-dulling are certainly contributing factors in limiting the useful life of any cutting edge, corrosion damage has also been found to be a major cause of dull edges on cutting edges in general and on shaving devices in particular.
Corrosion typically occurs when the free electrons in the metallic razor blade flow across the boundary edge and into the water shaving solution. Razor blades are normally made of ferromagnetic materials which act as conductors with large numbers of these free electrons. These electrons accumulate on the sharp cutting edge of the blade in an uneven manner and these uneven accumulations begin to act like electrodes which release these accumulated electrons from the cutting edge. These resultant metallic ions are absorbed by the water shaving solution thereby causing the gradual deterioration or corrosion of the metallic cutting edge.
Various blade sharpening devices are described by the prior art including some that purportedly use the effects of a magnetic field to restore and/or maintain the sharpness of the cutting edge of a given blade. For example, U.S. Pat. No. 1,775,518 issued to Forbes (1930) and U.S. Pat. No. 1,782,033 also issued to Forbes (1930) both describe the use of a magnetic influence to produce or maintain a good edge on a razor blade. Similarly, U.S. Pat. No. 2,321,570 issued to Billings (1940) disclosed a chamber containing magnets which would magnetically treat the blades stored therein. These types of sharpeners and many of their progeny were of limited commercial utility because they either required the use of large horseshoe-type magnets, which were both expensive and cumbersome, or they required specially configured magnets that were expensive and generally unavailable absent special production orders. Other devices, such as that disclosed by U.S. Pat. No. 2,792,108 issued to Keller (1957) purport to magnetically align the minute bends and distortions that occur in a razor blade during normal usage. However, this device required the use of magnets that were housed in a large rectangular chamber into which a razor blade or a razor with a razor blade attached would be inserted for reconditioning. In fact, most of the prior art required that the blade being sharpened be placed in some type of large, bulky vessel or container that seriously limited or negated its transportability,
The device disclosed by U.S. Pat. No. 4,615,436 issued to Hastie (1986) sought to overcome the shortcomings inherent in the aforementioned devices by providing a magnetic influence at an angle of 45 degrees incident to the plane of the blade so as to maintain the sharpness of the cutting edge. However, this device also required the use of magnets housed in a large rectangular chamber into which a razor with a razor blade attached would be inserted for reconditioning. This chamber was cumbersome and would typically use up a significant amount of space in a shaving kit or overnight bag which, in turn, restricted the user's ability to take the device with him while traveling. Further, even if the chamber were placed in a shaving kit or traveling bag, this device, like most, if not all of the prior art, had no means of keeping the blade securely fastened to the sharpening device. The blade could easily be knocked loose from the sharpening device thereby interrupting the restoration and/or maintenance process and also exposing the user to the risk of cutting himself on the unprotected cutting edge.
Some inventors sought to overcome the bulky, horseshoe-magnet problem by using a linear, end-to-end alignment of rectangular-shaped bar magnets. For example, U.S. Pat. No. 5,329,699 issued to McCoy (1994) and U.S. Pat. No. 5,638,042 also issued to McCoy (1997) disclose a linear, end-to-end alignment of magnets in a device that essentially fits over the object's cutting edge. U.S. Pat. No. 4,615,436 issued to Hastie (1986) also discloses a linear, end-to-end placement of magnets, albeit at a 45-degree angle to the plane of the blade being sharpened. However, these devices, as well as all other prior art disclosing a linear disposition of bar magnets, teach a linear alignment with opposite poles adjacent to one another. In fact, the prior art stresses the “scientific necessity” of aligning such magnets with opposite poles adjacent to one another. Further these devices, like all other devices disclosed by the prior art could only be placed on a horizontal surface where it would necessarily take up space that the owner might want to remain otherwise uncluttered.
Further, most of the prior art teaches blade-sharpening devices that are limited to use with shaving razors. U.S. Pat. No. 5,638,042 issued to McCoy (1997) discloses a device that fits over a generic cutting edge but this device, like all of the other prior art, teaches an alignment of magnets whereby opposite poles are adjacent to one another.